This invention relates to an electrostatic cleaning device, and more particularly to a portable electrostatic air cleaning device having a minimal depthwise air-flow dimension.
Electrostatic precipitators of air cleaning devices are well-known in the art. Such devices usually include two stages for treating the air, a first ionizing stage and a second collector stage. In the ionizing stage, the air moves past one or more ionizing wires from which are spaced ground electrodes to provide an electrostatic field in which the particles in the air are ionized or electrically charged. The ionized particles then move through the second collector stage, which constitutes a plurality of alternately charged and grounded parallel collector plates creating electric fields. The ionized particles are attracted to one collector plate or the other, depending upon the charge on the particle. The air then leaves the second stage, minus the particles, in a cleaner and more purified state.
Most electrostatic precipitators are provided with power packs, most of which include a voltage doubling circuit for applying a voltage to the ionized wires approximately twice as great as the voltage applied to the collector plates.
Examples of the above types of electrostatic precipitators are disclosed in prior U.S. Pat. Nos. 1,343,285 of Schmidt; 1,992,974 of Thompson; 2,813,595 of Fields; 2,925,881 of Berly et al; and 3,665,679 of McLain et al.
In conventional heating and air conditioning ducts, an ordinary type of air filter, such as a screen having small pores or openings to mechanically classify or separate large particles from the air stream, is removably supported in tracks transversely within the air duct normal to the air flow. The depthwise dimension or air-flow dimension of such mechanical filters is small and usually about one inch.
Although electrostatic precipitators of the type above described, including two stages of separation, may be mounted within conventional air ducts, nevertheless considerable alteration of the existing ducts must be made in order to properly mount such precipitators within the duct. The two-stage electrostatic precipitators are not only bulky, but have a substantial depthwise dimension. Thus, the existing two-stage electrostatic precipitators are not adapted to be substituted for conventional mechanical heating or air conditioning filters.